Absorption and Scattering 2D Volcano Images from Numerically Calculated Space-weighting functions

Edoardo Del Pezzo, Jesus Ibanez, Janire Prudencio, Francesca Bianco, Luca De Siena

Research output: Contribution to journalArticle

16 Citations (Scopus)
6 Downloads (Pure)

Abstract

Short period small magnitude seismograms mainly comprise scattered waves in the form of coda waves (the tail part of the seismogram, starting after S-waves and ending when the noise prevails), spanning more than 70% of the whole seismogram duration. Corresponding coda envelopes provide important information about the earth inhomogeneity, which can be stochastically modeled in terms of distribution of scatterers in a random medium. In suitable experimental conditions (i.e. high earth heterogeneity) either the two parameters describing heterogeneity (scattering coefficient), intrinsic energy dissipation (coefficient of intrinsic attenuation) or a combination of them (extinction length and seismic albedo) can be used to image Earth structures. Once a set of such parameter couples has been measured in a given area and for a number of sources and receivers, imaging their space distribution with standard methods is straightforward. However, as for finite-frequency and full-waveform tomography, the essential problem for a correct imaging is the determination of the weighting function describing the spatial sensitivity of observable data to scattering and absorption anomalies. Due to the nature of coda waves, the measured parameter-couple can be seen as a weighted space average of the real parameters characterizing the rock volumes illuminated by the scattered waves. This paper uses the Monte Carlo numerical solution of the Energy Transport Equation to find approximate but realistic 2D space-weighting functions for coda waves. Separate images for scattering and absorption based on these sensitivity functions are then compared with those obtained with commonly-used sensitivity functions in an application to data from an active seismic experiment carried out at Deception Island (Antarctica). Results show the that these novel functions are based on a reliable and physically grounded method to image magnitude and shape of scattering and absorption anomalies. Their extension to 3D holds promise to improve our ability to model volcanic structures using coda waves.
Original languageEnglish
Pages (from-to)742-756
Number of pages15
JournalGeophysical Journal International
Volume206
Issue number2
Early online date28 Apr 2016
DOIs
Publication statusPublished - Aug 2016

Fingerprint

weighting functions
Volcanoes
coda
volcanoes
volcano
scattering
Scattering
seismogram
seismograms
Earth (planet)
sensitivity
anomaly
deception
Earth structure
anomalies
energy dissipation
inhomogeneity
Imaging techniques
scattering coefficients
tomography

Keywords

  • tomography
  • seismic attenuation
  • seismic tomography
  • wave scattering and diffraction

Cite this

Absorption and Scattering 2D Volcano Images from Numerically Calculated Space-weighting functions. / Del Pezzo, Edoardo; Ibanez, Jesus; Prudencio, Janire; Bianco, Francesca; De Siena, Luca.

In: Geophysical Journal International, Vol. 206, No. 2, 08.2016, p. 742-756.

Research output: Contribution to journalArticle

Del Pezzo, Edoardo ; Ibanez, Jesus ; Prudencio, Janire ; Bianco, Francesca ; De Siena, Luca. / Absorption and Scattering 2D Volcano Images from Numerically Calculated Space-weighting functions. In: Geophysical Journal International. 2016 ; Vol. 206, No. 2. pp. 742-756.
@article{db0d9841e59649dca6c044be146e1c43,
title = "Absorption and Scattering 2D Volcano Images from Numerically Calculated Space-weighting functions",
abstract = "Short period small magnitude seismograms mainly comprise scattered waves in the form of coda waves (the tail part of the seismogram, starting after S-waves and ending when the noise prevails), spanning more than 70{\%} of the whole seismogram duration. Corresponding coda envelopes provide important information about the earth inhomogeneity, which can be stochastically modeled in terms of distribution of scatterers in a random medium. In suitable experimental conditions (i.e. high earth heterogeneity) either the two parameters describing heterogeneity (scattering coefficient), intrinsic energy dissipation (coefficient of intrinsic attenuation) or a combination of them (extinction length and seismic albedo) can be used to image Earth structures. Once a set of such parameter couples has been measured in a given area and for a number of sources and receivers, imaging their space distribution with standard methods is straightforward. However, as for finite-frequency and full-waveform tomography, the essential problem for a correct imaging is the determination of the weighting function describing the spatial sensitivity of observable data to scattering and absorption anomalies. Due to the nature of coda waves, the measured parameter-couple can be seen as a weighted space average of the real parameters characterizing the rock volumes illuminated by the scattered waves. This paper uses the Monte Carlo numerical solution of the Energy Transport Equation to find approximate but realistic 2D space-weighting functions for coda waves. Separate images for scattering and absorption based on these sensitivity functions are then compared with those obtained with commonly-used sensitivity functions in an application to data from an active seismic experiment carried out at Deception Island (Antarctica). Results show the that these novel functions are based on a reliable and physically grounded method to image magnitude and shape of scattering and absorption anomalies. Their extension to 3D holds promise to improve our ability to model volcanic structures using coda waves.",
keywords = "tomography, seismic attenuation, seismic tomography, wave scattering and diffraction",
author = "{Del Pezzo}, Edoardo and Jesus Ibanez and Janire Prudencio and Francesca Bianco and {De Siena}, Luca",
note = "Acknowledgments Yosuke Aoki and an anonymous reviewer greatly improved the quality of the paper. All calculations were made with Mathematica-10TM. Discussions with Marie Calvet, Danilo Galluzzo, Mario La Rocca, Salvatore De Lorenzo, Jessie Mayor and Ludovic Margerin are gratefully acknowledged. The authors are supported by MEDSUV European project and by Spanish Project Ephestos, CGL2011-29499-C02-01 and NOWAVES, TEC2015-68752. The TIDES EU travel Cost action provided travel money to support cooperation between Luca De Siena and the other authors.",
year = "2016",
month = "8",
doi = "10.1093/gji/ggw171",
language = "English",
volume = "206",
pages = "742--756",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Absorption and Scattering 2D Volcano Images from Numerically Calculated Space-weighting functions

AU - Del Pezzo, Edoardo

AU - Ibanez, Jesus

AU - Prudencio, Janire

AU - Bianco, Francesca

AU - De Siena, Luca

N1 - Acknowledgments Yosuke Aoki and an anonymous reviewer greatly improved the quality of the paper. All calculations were made with Mathematica-10TM. Discussions with Marie Calvet, Danilo Galluzzo, Mario La Rocca, Salvatore De Lorenzo, Jessie Mayor and Ludovic Margerin are gratefully acknowledged. The authors are supported by MEDSUV European project and by Spanish Project Ephestos, CGL2011-29499-C02-01 and NOWAVES, TEC2015-68752. The TIDES EU travel Cost action provided travel money to support cooperation between Luca De Siena and the other authors.

PY - 2016/8

Y1 - 2016/8

N2 - Short period small magnitude seismograms mainly comprise scattered waves in the form of coda waves (the tail part of the seismogram, starting after S-waves and ending when the noise prevails), spanning more than 70% of the whole seismogram duration. Corresponding coda envelopes provide important information about the earth inhomogeneity, which can be stochastically modeled in terms of distribution of scatterers in a random medium. In suitable experimental conditions (i.e. high earth heterogeneity) either the two parameters describing heterogeneity (scattering coefficient), intrinsic energy dissipation (coefficient of intrinsic attenuation) or a combination of them (extinction length and seismic albedo) can be used to image Earth structures. Once a set of such parameter couples has been measured in a given area and for a number of sources and receivers, imaging their space distribution with standard methods is straightforward. However, as for finite-frequency and full-waveform tomography, the essential problem for a correct imaging is the determination of the weighting function describing the spatial sensitivity of observable data to scattering and absorption anomalies. Due to the nature of coda waves, the measured parameter-couple can be seen as a weighted space average of the real parameters characterizing the rock volumes illuminated by the scattered waves. This paper uses the Monte Carlo numerical solution of the Energy Transport Equation to find approximate but realistic 2D space-weighting functions for coda waves. Separate images for scattering and absorption based on these sensitivity functions are then compared with those obtained with commonly-used sensitivity functions in an application to data from an active seismic experiment carried out at Deception Island (Antarctica). Results show the that these novel functions are based on a reliable and physically grounded method to image magnitude and shape of scattering and absorption anomalies. Their extension to 3D holds promise to improve our ability to model volcanic structures using coda waves.

AB - Short period small magnitude seismograms mainly comprise scattered waves in the form of coda waves (the tail part of the seismogram, starting after S-waves and ending when the noise prevails), spanning more than 70% of the whole seismogram duration. Corresponding coda envelopes provide important information about the earth inhomogeneity, which can be stochastically modeled in terms of distribution of scatterers in a random medium. In suitable experimental conditions (i.e. high earth heterogeneity) either the two parameters describing heterogeneity (scattering coefficient), intrinsic energy dissipation (coefficient of intrinsic attenuation) or a combination of them (extinction length and seismic albedo) can be used to image Earth structures. Once a set of such parameter couples has been measured in a given area and for a number of sources and receivers, imaging their space distribution with standard methods is straightforward. However, as for finite-frequency and full-waveform tomography, the essential problem for a correct imaging is the determination of the weighting function describing the spatial sensitivity of observable data to scattering and absorption anomalies. Due to the nature of coda waves, the measured parameter-couple can be seen as a weighted space average of the real parameters characterizing the rock volumes illuminated by the scattered waves. This paper uses the Monte Carlo numerical solution of the Energy Transport Equation to find approximate but realistic 2D space-weighting functions for coda waves. Separate images for scattering and absorption based on these sensitivity functions are then compared with those obtained with commonly-used sensitivity functions in an application to data from an active seismic experiment carried out at Deception Island (Antarctica). Results show the that these novel functions are based on a reliable and physically grounded method to image magnitude and shape of scattering and absorption anomalies. Their extension to 3D holds promise to improve our ability to model volcanic structures using coda waves.

KW - tomography

KW - seismic attenuation

KW - seismic tomography

KW - wave scattering and diffraction

U2 - 10.1093/gji/ggw171

DO - 10.1093/gji/ggw171

M3 - Article

VL - 206

SP - 742

EP - 756

JO - Geophysical Journal International

JF - Geophysical Journal International

SN - 0956-540X

IS - 2

ER -